新型长波红外折衍混合消热差系统

Novel Long Wavelength Infrared Diffractive/Refractive Athermal Optical System

为了提高大靶面高分辨率光学系统的性能,基于衍射元件独特的温度特性以及热补偿理论,设计了工作波段为8-12μm、视场角为16°、F/#为1.9、后工作距为133 mm的新型折衍混合消热差系统.系统采用三片式结构,使用锗和硒化锌两种常用的红外材料,仅引入一个二次非球面和一个衍射面,使系统具有结构简单、体积小、重量轻、成本低等优点.实验结果表明：系统在较大视场内成像质量接近衍射极限,且在-30℃～70℃温度范围内性能稳定,适用于像元尺寸为35μm,像元数为640×480的现代非制冷型焦平面阵列探测器,从而实现了消热差设计.

To improve performance of a large area high resolution optical system,a novel infrared diffractive-refractive hybrid system in 8-12 μm with 16° FOV is designed based on the thermal properties of the diffractive lens and the theory of athermalization.The effective focal length and back working distance of the system are respectively 100 mm and 133 mm,while the F number is 1.9.The system is composed of three lenses,which used only two materials of Ge and ZnSe,including a conic surface and a diffractive surface.The results show that the hybrid system possesses better athermal performances and high image quality in-30 ℃-70 ℃.Additionally,the system has a compact structure,lightweight,which make the system can satisfy the necessary specifications of modern optical instruments.